Semiconductor package system and method

ABSTRACT

A first protective layer is formed on a first die and a second die, and openings are formed within the first protective layer. The first die and the second die are encapsulated such that the encapsulant is thicker than the first die and the second die, and vias are formed within the openings. A redistribution layer can also be formed to extend over the encapsulant, and the first die may be separated from the second die.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a divisional of U.S. patent application Ser. No.14/447,371, entitled “Semiconductor Package System and Method,” filed onJul. 30, 2014, which application is incorporated herein by reference.

BACKGROUND

The semiconductor industry has experienced rapid growth due tocontinuous improvements in the integration density of a variety ofelectronic components (e.g., transistors, diodes, resistors, capacitors,etc.). For the most part, this improvement in integration density hascome from repeated reductions in minimum feature size (e.g., shrinkingthe semiconductor process node towards the sub-20 nm node), which allowsmore components to be integrated into a given area. As the demand forminiaturization, higher speed and greater bandwidth, as well as lowerpower consumption and latency has grown recently, there has grown a needfor smaller and more creative packaging techniques of semiconductordies.

As semiconductor technologies further advance, stacked and bondedsemiconductor devices have emerged as an effective alternative tofurther reduce the physical size of a semiconductor device. In a stackedsemiconductor device, active circuits such as logic, memory, processorcircuits and the like are fabricated at least partially on separatesubstrates and then physically and electrically bonded together in orderto form a functional device. Such bonding processes utilizesophisticated techniques, and improvements are desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a wafer with a first protective layer in accordancewith some embodiments.

FIG. 2 illustrates a singulation of the wafer into a first die and asecond die in accordance with some embodiments.

FIG. 3 illustrates an encapsulation of the first die and the second diein accordance with some embodiments;

FIGS. 4A-4B illustrate a formation of a seed layer in accordance withsome embodiments.

FIG. 5 illustrates a formation of vias and a redistribution layer inaccordance with some embodiments.

FIG. 6 illustrates a formation of a second protective layer inaccordance with some embodiments.

FIG. 7 illustrates a formation of underbump metallization and contactbumps in accordance with some embodiments.

FIG. 8 illustrates a separation of the first die from the second die inaccordance with some embodiments.

FIG. 9 illustrates an encapsulation of the first die and the second diewith through vias in accordance with some embodiments.

FIG. 10 illustrates a formation of the seed layer in electrical contactwith the through vias in accordance with some embodiments.

FIG. 11 illustrates a formation of the redistribution layer, theunderbump metallization, and the contact bumps in electrical connectionwith the through vias in accordance with some embodiments.

FIG. 12 illustrates a separation of the first die and the second diewith the through vias in accordance with some embodiments in accordancewith some embodiments.

FIGS. 13A-13C illustrate an enlarged cross section and two associatedtop down views of the contact pad, the via, the redistribution layer,and the through via in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

With reference now to FIG. 1, there is illustrated a wafer 100 with afirst die 101 and a second die 103 formed within and over the wafer 100,which will, in one embodiment be used in an integrated fanout (INFO)wafer level chip scale package (WLCSP) that is suitable for use in apackage on package (PoP) configuration. In an embodiment the first die101 and the second die 103 are formed within the wafer 100 separated bya first scribe region (represented in FIG. 1 by the dashed line labeled105) along which the wafer 100 will be separated to form the individualones of the first die 101 and the second die 103. In an embodiment thewafer 100 (and, as such, the first die 101 and the second die 103) maycomprise a substrate, first active devices, metallization layers (notseparately illustrated in FIG. 1), and contact pads 107. In anembodiment the substrate may comprise bulk silicon, doped or undoped, oran active layer of a silicon-on-insulator (SOI) substrate. Generally, anSOI substrate comprises a layer of a semiconductor material such assilicon, germanium, silicon germanium, SOI, silicon germanium oninsulator (SGOI), or combinations thereof. Other substrates that may beused include multi-layered substrates, gradient substrates, or hybridorientation substrates.

The first active devices comprise a wide variety of active devices andpassive devices such as capacitors, resistors, inductors and the likethat may be used to generate the desired structural and functional partsof the design for the first die 101 and the second die 103. The firstactive devices may be formed using any suitable methods either within orelse on the substrate.

The metallization layers are formed over the substrate and the firstactive devices and are designed to connect the various first activedevices to form functional circuitry for both the first die 101 and thesecond die 103. In an embodiment the metallization layers are formed ofalternating layers of dielectric and conductive material and may beformed through any suitable process (such as deposition, damascene, dualdamascene, etc.). In an embodiment there may be four layers ofmetallization separated from the substrate by at least one interlayerdielectric layer (ILD), but the precise number of metallization layersis dependent upon the design of the first die 101 and the second die103.

The contact pads 107 are formed in order to provide external contactsfor the metallization layers and the first active devices. In anembodiment the contact pads 107 are formed of a conductive material suchas aluminum, although other suitable materials, such as copper,tungsten, or the like, may alternatively be utilized. The contact pads107 may be formed using a process such as CVD or PVD, although othersuitable materials and methods may alternatively be utilized. Once thematerial for the contact pads 107 has been deposited, the material maybe shaped into the contact pads 107 using, e.g., a photolithographicmasking and etching process.

Over the first die 101 and the second die 103, a first protective layer109 may be placed and patterned. In an embodiment the first protectivelayer 109 may be a protective material such as polybenzoxazole (PBO) orpolyimide (PI), silicon oxide, silicon nitride, silicon oxynitride,benzocyclobutene (BCB), or any other suitable protective material. Thefirst protective layer 109 may be formed using a method such as aspin-on process, a deposition process (e.g., chemical vapor deposition),or other suitable process based upon the chosen material, and may beformed to a first thickness T₁ of between about 1 μm and about 100 μm,such as about 20 μm.

Once formed the first protective layer 109 is patterned to form viasopenings 111 and expose the contact pads 107. Additionally, the firstprotective layer 109 is patterned to form first openings 113 to exposethe scribe region 105. This exposure of the scribe region 105additionally recesses the first protective layer 109 from sidewalls ofthe first die 101 and the second die 103 such that sidewalls of thefirst protective layer 109 are laterally separated and not aligned withsidewalls of the first die 101 and the second die 103 after the firstdie 101 has been separated from the second die 103 (described furtherbelow with respect to FIG. 2).

In an embodiment the first protective layer 109 may be patterned using,e.g., a photolithographic masking and etching process. In such aprocess, a first photoresist (not individually illustrated in FIG. 1) isapplied to the first protective layer 109 and then exposed to apatterned light source. The light source will impinge upon the firstphotoresist and induce a change in a property of the first photoresist,which is then utilized to selectively remove either the exposed portionor the unexposed portion and expose the first protective layer 109. Thefirst photoresist is then utilized as a mask during, e.g., an etchingprocess which removes portions of the first protective layer 109 toexpose the contact pads 107. Once the first protective layer 109 hasbeen patterned, the first photoresist may be removed using, e.g., anashing process.

In an embodiment the via openings 111 may be formed to have a firstdiameter D₁ at the bottom of between about 1 μm and about 50 μm, such asabout 15 μm. Additionally, the first protective layer 109 may bepatterned to expose the scribe region 105 between the first die 101 andthe second die 103. For example, the first protective layer 109 may bepatterned to form the first opening 113 over the scribe region 105 witha first width W₁ of between about 20 μm and about 150 μm, such as about80 μm.

FIG. 2 illustrates that, once the via openings 111 have been formed, thewafer 100 in general and the first die 101 and the second die 103 inparticular may be thinned. In an embodiment the wafer 100 may be thinnedusing, e.g., chemical mechanical polishing, whereby a combination ofchemical reactants and abrasives are utilized with one or more grindingpads in order to remove portions of the wafer 100 opposite the contactpads 107. However, any other suitable process, such as a physicalgrinding process, an etching process, or combinations of these, mayalternatively be utilized. In an embodiment the wafer 100 is thinned tohave a second thickness T₂ of between about 30 μm and about 700 μm, suchas about 250 μm.

Once thinned, a die attach film (DAF) 201 may be applied to the firstdie 101 and the second die 103 in order to assist in the attachment ofthe first die 101 and the second die 103 to a carrier wafer 301 (notillustrated in FIG. 1 but illustrated and described below with respectto FIG. 3). In an embodiment the die attach film 201 is an expoy resin,a phenol resin, acrylic rubber, silica filler, or a combination thereof,and is applied using a lamination technique. However, any other suitablealternative material and method of formation may alternatively beutilized.

After the die attach film 201 has been applied, the first die 101 andthe second die 103 may be singulated and separated from the remainder ofthe wafer 100. In an embodiment a laser may be used to form grooveswithin the wafer 100 within the scribe region 105. Once the grooves havebeen formed, the singulation may be performed by using a saw blade(represented in FIG. 2 by the dashed box labeled 203) to slice the wafer100 within the scribe region 105 between the first die 101 and thesecond die 103, thereby separating the first die 101 and the second die102 from each other and separating the wafer 100 into the individualdies.

However, as one of ordinary skill in the art will recognize, utilizingthe saw blade 203 to singulate the first die 101 and the second die 103from the wafer 100 is merely one illustrative embodiment and is notintended to be limiting. Alternative methods for singulating the firstdie 101 and the second die 103, such as utilizing one or more etches toseparate the first die 101 and the second die 103 from the wafer 100,may alternatively be utilized. These methods and any other suitablemethods may alternatively be utilized to singulate the wafer 100 intothe first die 101 and the second die 103.

FIG. 3 illustrates an attachment of the first die 101 and the second die103 to a carrier wafer 301 and an encapsulation of the first die 101 andthe second die 103 with an encapsulant 303. In an embodiment the carrierwafer 301 may comprise, for example, glass, silicon oxide, aluminumoxide, and the like. The carrier wafer 301 may have a thickness that isgreater than about 12 mils. The first die 101 and the second die 103 maybe attached, e.g., using the die attach film 201 or other suitableadhesive.

Once attached to the carrier wafer 301, the first die 101 and the seconddie 103 may be encapsulated with the encapsulant 303 in order to provideprotection as well as to provide another surface for further processing(described further below with respect to FIGS. 3-8). In an embodimentthe encapsulant 303 may be a molding compound and may be placed using amolding device. For example, the first die 101 and the second die 103may be placed within a cavity of the molding device (not illustrated inFIG. 2), and the cavity may be hermetically sealed.

In an embodiment the first die 101 and the second die 103 are placedwithin the molding device such that the molding device covers the viaopenings 111 and the encapsulant 303 does not enter the via openings 111during the molding process. For example, in one embodiment, the moldingdevice comprises a top portion and a bottom portion that are broughtinto contact with each other in order to form the cavity between them.The first die 101 and the second die 103 are placed on the bottomportion and the top portion is lowered to be in physical contact withthe first protective layer 109 while forming the cavity. This contactbetween the top portion and the first protective layer 109 both formsthe cavity/hermetic seal for the molding process and also seals the viaopenings 111 such that no encapsulant 303 can enter the via openings 111during the encapsulation process.

However, as one of ordinary skill in the art will recognize, the use ofthe top portion of the molding device is merely one illustrativeembodiment and is not intended to limit the embodiments. Rather, anysuitable method of preventing the encapsulant 303 from entering the viaopenings 111 may alternatively be utilized. For example, a plate orother solid barrier may be placed in contact with the first protectivelayer 109 and covering the via openings 111 during the encapsulationprocess, or a material may be placed within the via openings 111 priorto the encapsulation process and then removed after the encapsulationprocess. All such processes are fully intended to be included within thescope of the embodiments.

Once the first die 101 and the second die 103 are within the cavity, theencapsulant 303 may be placed within the cavity either before the cavityis hermetically sealed or else may be injected into the cavity throughan injection port. In an embodiment the encapsulant 303 may be a moldingcompound resin such as polyimide, PPS, PEEK, PES, a heat resistantcrystal resin, combinations of these, or the like.

In an alternative embodiment, the encapsulant 303 may be chosen suchthat the encapsulant 303 has a dielectric function and such that a firstseed layer 401 (not illustrated in FIG. 3 but illustrated and describedbelow with respect to FIG. 4A) may be formed over and in physicalcontact with the encapsulant 303. For example, the encapsulant 303 maybe 20 μm, 300 μm, or 690 μm. By using these materials, a separatepassivation layer 405 (not illustrated in FIG. 3 but illustrated inanother embodiment in FIG. 4B below), may be avoided, simplifying theoverall process.

In an embodiment, the molding device is shaped to place the encapsulant303 such that it has a third thickness T₃ that is greater than the firstdie 101 and the second die 103. For example, in an embodiment in whichthe first die 101 has the second thickness T₂ of about 200 μm, theencapsulant 303 has the third thickness T₃ of between about 201 μm andabout 215 μm, such as about 210 μm. Additionally, in some embodimentsthe third thickness T₃, while being greater than the first thickness T₁,is less than the combined thickness of the first die 101 and the firstprotective layer 109 (T₁+T₂). As such, the sidewall of the firstprotective layer 109 may be partially covered by the encapsulant 303,with a portion of the sidewall being exposed and free from theencapsulant 303.

Additionally, because the first protective layer 901 has been recessedfrom the sidewalls of the first die 101 and the second die 103 (asdescribed above with respect to FIG. 1), the encapsulant 303 will extendover and be in physical contact with the top surface of the first die101 and the second die 103. As such, the encapsulant 303 will have astep shape as it covers a region between, e.g., the first die 101 andthe first protective layer 109 over the first die 101.

Once the encapsulant 303 has been placed into the cavity such that theencapsulant 303 encapsulates the region around the first die 101 and thesecond die 103, the encapsulant 303 may be cured in order to harden theencapsulant 303 for optimum protection. While the exact curing processis dependent at least in part on the particular material chosen for theencapsulant 303, in an embodiment in which molding compound is chosen asthe encapsulant 303, the curing could occur through a process such asheating the encapsulant 303 to between about 100° C. and about 130° C.,such as about 125° C. for about 60 sec to about 3000 sec, such as about600 sec. Additionally, initiators and/or catalysts may be includedwithin the encapsulant 303 to better control the curing process.

However, as one having ordinary skill in the art will recognize, thecuring process described above is merely an exemplary process and is notmeant to limit the current embodiments. Other curing processes, such asirradiation or even allowing the encapsulant 303 to harden at ambienttemperature, may alternatively be used. Any suitable curing process maybe used, and all such processes are fully intended to be included withinthe scope of the embodiments discussed herein.

Optionally, in some embodiments the encapsulant 303 may initially beplaced such that the third thickness T₃ is greater than the sum of thefirst thickness T₁ (for the first protective layer 109) and the secondthickness T₂ (for the first die 101). In this embodiment, an optionalplanarization process may be utilized to planarize the encapsulant 303with the first protective layer 109 (not separately illustrated in FIG.3). In this embodiment a suitable planarization process, such as achemical mechanical polishing process, a physical grinding process, or aseries of one or more etches may be used to planarize the encapsulant303 with the first protective layer 109.

FIG. 4A illustrates a formation of a first seed layer 401 along with asecond photoresist 403 formed and patterned over the first seed layer401. The first seed layer 401 is a thin layer of a conductive materialthat aids in the formation of a thicker layer during subsequentprocessing steps. The first seed layer 401 may comprise a layer oftitanium about 1,000 Å thick followed by a layer of copper about 5,000 Åthick. The first seed layer 401 may be created using processes such assputtering, evaporation, or PECVD processes, depending upon the desiredmaterials. The first seed layer 401 may be formed to have a thickness ofbetween about 0.3 μm and about 1 μm, such as about 0.5 μm.

In this embodiment, the first seed layer 401 is formed such that thefirst seed layer 401 extends into and lines the via openings 111.Additionally, in an embodiment in which the encapsulant 303 canwithstand the first seed layer 401, the first seed layer 401 also isformed over and in contact with the encapsulant 303, running along a topsurface of the encapsulant 303. As such, the first seed layer 401 isformed as a continuous, single layer of material that covers the exposedtop surface of the encapsulant 303 and the first protective layer 109over the first die 101 and the second die 103.

FIG. 4B illustrates an alternative embodiment, in which a passivationlayer 405 is formed over the encapsulant 303 prior to formation of thefirst seed layer 401. In an embodiment the passivation layer 405 may bepolybenzoxazole (PBO), although any suitable material, such as polyimideor a polyimide derivative, may alternatively be utilized. Thepassivation layer 405 may be placed using, e.g., a spin-coating processto a thickness of between about 5 μm and about 25 μm, such as about 7μm, although any suitable method and thickness may alternatively beused.

Returning now to the embodiment described in FIG. 4A, once the firstseed layer 401 has been formed, the second photoresist 403 may be placedand patterned over the first seed layer 401. In an embodiment the secondphotoresist 403 may be placed on the first seed layer 401 using, e.g., aspin coating technique to a height of between about 50 μm and about 250μm, such as about 120 μm. Once in place, the second photoresist 403 maythen be patterned by exposing the second photoresist 403 to a patternedenergy source (e.g., a patterned light source) so as to induce achemical reaction, thereby inducing a physical change in those portionsof the second photoresist 403 exposed to the patterned light source. Adeveloper is then applied to the exposed second photoresist 403 to takeadvantage of the physical changes and selectively remove either theexposed portion of the second photoresist 403 or the unexposed portionof the second photoresist 403, depending upon the desired pattern.

In an embodiment the pattern formed into the second photoresist 403 is apattern that exposes the via openings 111 so that the via openings 111may be filled in subsequent processing steps (described below withrespect to FIG. 5). Additionally, the patterning of the secondphotoresist 403 also exposes portions of the first protective layer 109and the encapsulant 303 (or, alternatively, the passivation layer 405)where a redistribution layer 501 (not illustrated in FIG. 4A butillustrated and described below with respect to FIG. 5) may be desired.Such a placement allows the area over the encapsulant 303 to be utilizedfor electrical routing and connection purposes.

FIG. 5 illustrates that, once the second photoresist 403 has beenpatterned, vias 503 and the redistribution layer 501 are formed withinthe second photoresist 403. In FIG. 5, the vias 503 are shown as beingseparate from the redistribution layer 501 by a dashed line labeled 505.However, this is intended for clarity and not necessarily a physicalseparation, as the vias 503 and the redistribution layer 501 may beformed using the same materials and same processes. Alternatively, ifdesired, the vias 503 may be formed separately from the redistributionlayer 501. Additionally, while the redistribution layer 501 and thefirst seed layer 401 are still illustrated as separate layers within thefigures, it is understood that the first seed layer 401 is actually apart of the redistribution layer 501.

In an embodiment the vias 503 and the redistribution layer 501 compriseone or more conductive materials, such as copper, tungsten, otherconductive metals, or the like, and may be formed, for example, byelectroplating, electroless plating, or the like. In an embodiment, anelectroplating process is used wherein the first seed layer 401 and thesecond photoresist 403 are submerged or immersed in an electroplatingsolution. The first seed layer 401 surface is electrically connected tothe negative side of an external DC power supply such that the firstseed layer 401 functions as the cathode in the electroplating process. Asolid conductive anode, such as a copper anode, is also immersed in thesolution and is attached to the positive side of the power supply. Theatoms from the anode are dissolved into the solution, from which thecathode, e.g., the first seed layer 401, acquires the dissolved atoms,thereby plating the exposed conductive areas of the first seed layer 401within the opening of the second photoresist 403.

Once the vias 503 and the redistribution layer 501 have been formedusing the second photoresist 403 and the first seed layer 401, thesecond photoresist 403 may be removed using a suitable removal process.In an embodiment, a plasma ashing process may be used to remove thesecond photoresist 403, whereby the temperature of the secondphotoresist 403 may be increased until the second photoresist 403experiences a thermal decomposition and may be removed. However, anyother suitable process, such as a wet strip, may alternatively beutilized. The removal of the second photoresist 403 may expose theunderlying portions of the first seed layer 401.

After the removal of the second photoresist 403 exposes the underlyingfirst seed layer 401, these portions are removed. In an embodiment theexposed portions of the first seed layer 401 (e.g., those portions thatare not covered by the vias 503 and the redistribution layer 501) may beremoved by, for example, a wet or dry etching process. For example, in adry etching process reactants may be directed towards the first seedlayer 401, using the vias 503 and the redistribution layer 501 as masks.Alternatively, etchants may be sprayed or otherwise put into contactwith the first seed layer 401 in order to remove the exposed portions ofthe first seed layer 401.

FIG. 6 illustrates a placement and patterning of a second protectivelayer 601. In an embodiment the second protective layer 601 may besimilar to the first protective layer 109 (described above with respectto FIG. 1). For example, the second protective layer 601 may be a PBO orpolyimide material placed using a spin-on process. However, in otherembodiments the second protective layer 601 is different from the firstprotective layer 109, and any suitable material and method ofmanufacture may alternatively be utilized. In an embodiment the secondprotective layer 601 may be formed to have a fourth thickness T₄ ofbetween about 1 μm and about 10 μm, such as about 4 μm.

Once formed, the second protective layer 601 may be patterned to formsecond openings 603 and to expose portions of the redistribution layer501 over the encapsulant 303 and third openings 605. In an embodimentthe second protective layer 601 may be patterned using, e.g., aphotolithographic masking and etching process. In such a process, athird photoresist (not individually illustrated in FIG. 6) is applied tothe second protective layer 601 and then exposed to a patterned lightsource. The light source will impinge upon the third photoresist andinduce a change in a property of the third photoresist, which is thenutilized to selectively remove either the exposed portion or theunexposed portion and expose the second protective layer 601. The thirdphotoresist is then utilized as a mask during, e.g., an etching processwhich removes portions of the second protective layer 601 to expose theredistribution layer 501. Once the second protective layer 601 has beenpatterned, the third photoresist may be removed using, e.g., an ashingprocess.

In an embodiment the second openings 603 may be formed to have a seconddiameter D₂ at the bottom of between about 2 μm and about 30 μm, such asabout 10 μm. Additionally, while the second openings 603 in thisembodiment have been illustrated and described as exposing a portion ofthe redistribution layer 501 over the encapsulant 303, this is onlyintended to be illustrative and is not intended to be limiting to theembodiments. Rather, the second openings 603 may be formed to expose anydesired portions of the redistribution layer 501. All such exposures arefully intended to be included within the scope of the embodiments.

Additionally, the third openings 605 may also be formed over a regionbetween the first die 101 and the second die 103 in preparation for aneventual separation (described further below with respect to FIG. 8). Inthis region, the third openings 605 may have a second width W₂ ofbetween about 20 μm and about 150 μm, such as about 80 μm. Such aformation will also recess sidewalls of the second protective layer 601away from sidewalls of the encapsulant 303 once the first die 101 hasbeen separated from the second die 103 (described below with respect toFIG. 8).

FIG. 7 illustrates a formation of underbump metallizations (UBM) 701within the vias 503 and contact bumps 703. The UBM 701 may comprisethree layers of conductive materials, such as a layer of titanium, alayer of copper, and a layer of nickel. However, one of ordinary skillin the art will recognize that there are many suitable arrangements ofmaterials and layers, such as an arrangement of chrome/chrome-copperalloy/copper/gold, an arrangement of titanium/titanium tungsten/copper,or an arrangement of copper/nickel/gold, that are suitable for theformation of the UBM 701. Any suitable materials or layers of materialthat may be used for the UBM 701 are fully intended to be includedwithin the scope of the embodiments.

In an embodiment the UBM 701 is created by forming each layer over theredistribution layer 501 and along the interior of the second opening603 through the second protective layer 601. The forming of each layermay be performed using a plating process, such as electrochemicalplating, although other processes of formation, such as sputtering,evaporation, or PECVD process, may alternatively be used depending uponthe desired materials. The UBM 701 may be formed to have a thickness ofbetween about 0.7 μm and about 10 μm, such as about 5 μm.

The contact bumps 703 may comprise a material such as tin, or othersuitable materials, such as silver, lead-free tin, or copper. In anembodiment in which the contact bumps 703 are tin solder bumps, thecontact bumps 703 may be formed by initially forming a layer of tinthrough such commonly used methods such as evaporation, electroplating,printing, solder transfer, ball placement, etc, to a thickness of, e.g.,about 100 μm. Once a layer of tin has been formed on the structure, areflow may be performed in order to shape the material into the desiredbump shape.

FIG. 8 illustrates a removal of the carrier wafer 301 as well as aseparation of the first die 101 from the second die 103 to form apackage 801 such as an integrated fan out package. In an embodiment thecarrier wafer 301 may be removed by a physical, thermal, or ultravioletprocess, depending upon the material chosen for the die attach film 201.In an embodiment in which the die attach film 201 thermally decomposes,the die attach film 201 may be heated, causing it to reduce or lose itsadhesiveness. The carrier wafer 301 may then be physically separatedfrom the first die 101 and the second die 103.

Once the carrier wafer 100 has been removed, the first die 101 may beseparated from the second die 103. In an embodiment the separation maybe performed by using the saw blade 203 (described above with respect toFIG. 2) to slice a region of the encapsulant 303 between the first die101 and the second die 103, thereby separating the first die 101 fromthe second die 102. However, any suitable method, such as a series ofone or more etches or initially forming grooves prior to sawing, mayalternatively be used, and all such methods are fully intended to beincluded within the scope of the embodiments.

By forming the vias 503 prior to the encapsulation, the die shift windowcan be enlarged because the land of the trace can be a customized designto cover the via opening. Additionally, by forming the via 503 first,the usual step of grinding to expose the vias 503 can be eliminated,saving cost and simplifying the process. This also allows the vias 503to be adopted for an integrated fan out, wafer level chip scale package(INFO WLCSP).

FIGS. 9-12 illustrate another embodiment which utilizes through vias 901that extend through the encapsulant 303 to electrically connect theredistribution layer 501 to an opposite side of the package 801. In thisembodiment, prior to the first die 101 and the second die 103 beingattached to the carrier wafer 301, the through vias 901 are formed overthe carrier wafer 301 by initially forming an adhesive layer 903, apolymer layer 905, and a second seed layer 907 (illustrated with FIG. 9already patterned) on the carrier wafer 301.

In an embodiment the adhesive layer 903 is placed on the carrier wafer301 in order to assist in the adherence of overlying structures (e.g.,the polymer layer 905). In an embodiment the adhesive layer 903 maycomprise an ultra-violet glue, which loses its adhesive properties whenexposed to ultra-violet light. However, other types of adhesives, suchas pressure sensitive adhesives, radiation curable adhesives, epoxies,combinations of these, or the like, may also be used. The adhesive layer903 may be placed onto the carrier wafer 301 in a semi-liquid or gelform, which is readily deformable under pressure.

The polymer layer 905 is placed over the adhesive layer 903 and isutilized in order to provide protection to, e.g., the first die 101 andthe second die 103 once the first die 101 and the second die 103 havebeen attached. In an embodiment the polymer layer 905 may bepolybenzoxazole (PBO), although any suitable material, such as polyimideor a polyimide derivative, may alternatively be utilized. The polymerlayer 905 may be placed using, e.g., a spin-coating process to athickness of between about 2 μm and about 15 μm, such as about 5 μm,although any suitable method and thickness may alternatively be used.

The second seed layer 907 is a thin layer of a conductive material thataids in the formation of a thicker layer during subsequent processingsteps to form the through vias 901. The second seed layer 907 maycomprise a layer of titanium about 1,000 Å thick followed by a layer ofcopper about 5,000 Å thick. The second seed layer 907 may be createdusing processes such as sputtering, evaporation, or PECVD processes,depending upon the desired materials. The second seed layer 907 may beformed to have a thickness of between about 0.3 μm and about 1 μm, suchas about 0.5 μm.

Once the second seed layer 907 has been formed, a fourth photoresist(not illustrated in FIG. 9) may be placed and patterned over the secondseed layer 907. In an embodiment the fourth photoresist may be placed onthe second seed layer 907 using, e.g., a spin coating technique to aheight of between about 50 μm and about 250 μm, such as about 120 μm.Once in place, the fourth photoresist may then be patterned by exposingthe fourth photoresist to a patterned energy source (e.g., a patternedlight source) so as to induce a chemical reaction, thereby inducing aphysical change in those portions of the fourth photoresist exposed tothe patterned light source. A developer is then applied to the exposedfourth photoresist to take advantage of the physical changes andselectively remove either the exposed portion of the fourth photoresistor the unexposed portion of the fourth photoresist, depending upon thedesired pattern.

In an embodiment the pattern formed into the fourth photoresist is apattern for the through vias 901. The through vias 901 are formed insuch a placement as to be located on different sides of subsequentlyattached devices such as the first die 101 and the second die 103.However, any suitable arrangement for the pattern of through vias 901may alternatively be utilized.

Once the fourth photoresist has been patterned, the through vias 901 areformed within the fourth photoresist. In an embodiment the through vias901 comprise one or more conductive materials, such as copper, tungsten,other conductive metals, or the like, and may be formed, for example, byelectroplating, electroless plating, or the like. In an embodiment, anelectroplating process is used wherein the second seed layer 907 and thefourth photoresist are submerged or immersed in an electroplatingsolution. The second seed layer 907 surface is electrically connected tothe negative side of an external DC power supply such that the secondseed layer 907 functions as the cathode in the electroplating process. Asolid conductive anode, such as a copper anode, is also immersed in thesolution and is attached to the positive side of the power supply. Theatoms from the anode are dissolved into the solution, from which thecathode, e.g., the second seed layer 907, acquires the dissolved atoms,thereby plating the exposed conductive areas of the second seed layer907 within the opening of the fourth photoresist.

Once the through vias 901 have been formed using the fourth photoresistand the second seed layer 907, the fourth photoresist may be removedusing a suitable removal process. In an embodiment, a plasma ashingprocess may be used to remove the fourth photoresist, whereby thetemperature of the fourth photoresist may be increased until the fourthphotoresist experiences a thermal decomposition and may be removed.However, any other suitable process, such as a wet strip, mayalternatively be utilized. The removal of the fourth photoresist mayexpose the underlying portions of the second seed layer 907.

After the removal of the fourth photoresist exposes the underlyingsecond seed layer 907, these portions are removed. In an embodiment theexposed portions of the second seed layer 907 (e.g., those portions thatare not covered by the through vias 901) may be removed by, for example,a wet or dry etching process. For example, in a dry etching processreactants may be directed towards the second seed layer 907, using thethrough vias 901 as masks. Alternatively, etchants may be sprayed orotherwise put into contact with the second seed layer 907 in order toremove the exposed portions of the second seed layer 907. After theexposed portion of the second seed layer 907 has been etched away, aportion of the polymer layer 905 is exposed between the through vias901.

Once the through vias 901 have been formed, the first die 101 and thesecond die 103 are placed on the carrier wafer 301 (in contact with thepolymer layer 905) using, e.g., the die attach film 201. Once attached,the first die 101, the second die 103, and the through vias 901 may beencapsulated by the encapsulant 303 as described above with respect toFIG. 3. For example, the first die 101, the second die 103, and thethrough vias 901 may be placed into a molding device (not illustrated inFIG. 9) and the encapsulant 303 may be placed into the molding deviceand then cured.

After the encapsulant 303 has been placed and cured, a planarizationprocess may be performed in order to planarize the encapsulant 303, thethrough vias 901, and the first protective layer 109 and to expose thethrough vias 901. In an embodiment the planarization process may be,e.g., a chemical mechanical polishing process, although any suitableprocess, such as physical grinding or etching, may alternatively beused.

FIG. 10 illustrates a placement of the first seed layer 401 within thevia openings 111 as well as over the first protective layer 109, theencapsulant 303, and in electrical connection with the through vias 901.The first seed layer 401 may be formed as described above with respectto FIG. 4. For example, the first seed layer 401 may be copper formed bysputtering, although any suitable material and process may alternativelybe utilized. However, by forming the first seed layer 401 in electricalconnection with the through vias 901, the first seed layer iselectrically connected to a second side of the package 801, allowing forelectrical connection to electrical routing, either through an externalconnection (e.g. a bump or copper pillar), or else to anotherredistribution layer formed on the opposite side of the package 801.

Additionally, FIG. 10 also illustrates the formation of the secondphotoresist 403 over the first seed layer 401. In this embodiment, thesecond photoresist 403 may be placed and exposed as described above withrespect to FIG. 4. However, the second photoresist 403 is patterned soas to not be located over the through vias 901.

FIG. 11 illustrates a formation of the redistribution layer 501, thesecond protective layer 601, the UBM 701, and the contact bumps 703.These may be formed as described above with respect to FIGS. 4-7.However, with the inclusion of the through vias 901, the redistributionlayer 501, the UBMs 701 and the contact bumps 703 are electricallyconnected to the through vias 901 and, consequently, to the second sideof the package.

FIG. 12 illustrates a separation of the first die 101 from the seconddie 103 to form the package 801 using, e.g., a laser grooving ordrilling process followed by the saw blade 203 being used to separatethe first die 101 from the second die 103. However, in this embodimentthe package 801 also comprises the through vias 901 that connect theredistribution layer 501 with the second side of the package 801opposite the redistribution layer 501. Such a connection allows forfurther options for electrical routing around the package 801.

FIGS. 13A-13C illustrate an enlarged cross section and two associatedtop down views of the contact pad 107, the via 503, the redistributionlayer 501, and the through via 901, with FIGS. 13B and 13C being topdown views of FIG. 13A along line A-A′. By forming the openings for thevias 503 prior to attaching the dies (e.g., the first die 101 and thesecond die 103) to the carrier wafer 301, and then forming theredistribution layer 501 over the via 503, only the size of the land forthe redistribution layer 501 needs to be considered in order to coverthe die shift that occurs. As such, the die shift window is enlarged andit the bonding accuracy can be increased.

This is illustrated by the top down views of FIGS. 13B and 13C. In FIG.13B, there is a chip shift in a first direction. However, due to theembodiments as described above, the redistribution layer 501 can stillcompensate for it in this direction. Additionally, as illustrated inFIG. 13C, even a chip shift in a different direction can also becompensated for by enlarging the land of the redistribution layer 501over contact pad 107 and the via 503.

In accordance with an embodiment, a semiconductor device comprising asemiconductor die, the semiconductor die comprising a first side, asecond side opposite the first side, and a first sidewall extendingbetween the first side and the second side, is provided. A protectivelayer is over the semiconductor die, the protective layer comprising asecond sidewall. Vias extend through the protective layer, and anencapsulant encapsulates the semiconductor die, the encapsulant inphysical contact with the first side, the first sidewall, and a firstportion of the second sidewall, wherein a second portion of the secondsidewall is not in physical contact with the encapsulant.

In accordance with another embodiment, a semiconductor device comprisinga semiconductor die with a first sidewall and a first protective layerover the semiconductor die, wherein a second sidewall of the firstprotective layer is recessed from the first sidewall of thesemiconductor die, is provided. An opening is through the firstprotective layer, and an encapsulant covers the first sidewall and thesecond sidewall, wherein the encapsulant has a top surface that isplanar with the first protective layer. A conductive material fills theopening and extending over the encapsulant.

In accordance with another embodiment, a method of manufacturing asemiconductor device comprising forming a first protective layer over afirst die and a second die and encapsulating the first die and thesecond die with an encapsulant, wherein the encapsulant has a greaterthickness than the first die is provided. A conductive material isformed that extends through the first protective layer and extends overthe encapsulant.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A semiconductor device comprising: asemiconductor die with a first sidewall; a first protective layer overthe semiconductor die, wherein a second sidewall of the first protectivelayer is recessed from the first sidewall of the semiconductor die; anopening through the first protective layer; an encapsulant covering thefirst sidewall and the second sidewall, wherein the encapsulant has atop surface that is planar with the first protective layer; a conductivematerial filling the opening and extending over the encapsulant; and athrough via extending through the encapsulant and in electricalconnection with the conductive material.
 2. The semiconductor device ofclaim 1, further comprising a second protective layer over theconductive material.
 3. The semiconductor device of claim 2, furthercomprising an underbump metallization extending through the secondprotective layer to make electrical contact with the conductivematerial.
 4. The semiconductor device of claim 2, wherein the secondprotective layer has a third sidewall aligned with a fourth sidewall ofthe encapsulant.
 5. The semiconductor device of claim 1, wherein theconductive material is in physical contact with the encapsulant.
 6. Thesemiconductor device of claim 5, wherein the conductive material iscopper.
 7. A semiconductor device comprising: a protective materialoverlying a first surface of a semiconductor die, the protectivematerial having a second surface facing away from the first surface; anencapsulant encapsulating the protective material and the semiconductordie, wherein the encapsulant extends at least partially over the firstsurface and wherein the encapsulant has a third surface that is planarwith the second surface; and a conductive material extending through theprotective material to make electrical contact with the semiconductordie, the conductive material also extending over the third surface,wherein the conductive material comprises a seed layer.
 8. Thesemiconductor device of claim 7, wherein the conductive material is aredistribution layer.
 9. The semiconductor device of claim 8, furthercomprising a second protective layer at least partially covering theredistribution layer.
 10. The semiconductor device of claim 9, furthercomprising an underbump metallization extending through the secondprotective layer and in contact with the redistribution layer.
 11. Thesemiconductor device of claim 7, further comprising a through viaextending through the encapsulant.
 12. The semiconductor device of claim11, wherein the through via is in physical contact with the conductivematerial.
 13. A semiconductor device comprising: a first surface,wherein the first surface comprises a protective material and anencapsulating material, wherein the protective material extends a firstdistance from the first surface to a second surface opposite the firstsurface and wherein the encapsulating material extends a second distancefrom the first surface to a third surface opposite the first surface,the second distance being greater than the first distance; asemiconductor die in physical contact with the second surface of theprotective material, wherein the semiconductor die extends a thirddistance from the second surface to a fourth surface facing away fromthe second surface, wherein the second distance is at least as large asa sum of the first distance and the third distance, and wherein theprotective material has a first width and the semiconductor die has asecond width greater than the first width; and a conductive materialextending over both the protective material and the encapsulatingmaterial, the conductive material also extending through the protectivematerial to be in electrical contact with the semiconductor die, whereinthe conductive material comprises a seed layer.
 14. The semiconductordevice of claim 13, further comprising a through via within theencapsulating material, the through via having a first height at leastas large as the second distance.
 15. The semiconductor device of claim14, wherein the through via is physically in contact with the conductivematerial.
 16. The semiconductor device of claim 13, further comprisingan underbump metallization in electrical connection with the conductivematerial.
 17. The semiconductor device of claim 16, wherein theunderbump metallization is in physical contact with the conductivematerial.
 18. The semiconductor device of claim 1, wherein theconductive material is a redistribution layer.
 19. The semiconductordevice of claim 1, wherein the through via is in physical contact withthe conductive material.
 20. The semiconductor device of claim 3,further comprising an external connection in physical contact with theunderbump metallization.